The suspected gas attack on April 7 on Douma, near Damascus, reportedly left more than 40 people dead and was blamed by Western powers on the regime of Syrian President Bashar al-Assad.

In response, the United States, France and Britain conducted unprecedented missile strikes on Syrian military installations, but Paris admitted on Tuesday they were a matter of "honour" that had solved nothing.

"Experts from the chemical weapons committee enter the town of Douma," state news agency SANA wrote, referring to the Organisation for the Prohibition of Chemical Weapons (OPCW).

The inspectors arrived in Damascus on the day of the Western strikes but had not been allowed to enter Douma.

Around 70 people are estimated to have been killed in the chemical weapons attackCredit:
HASAN MOHAMED/AFP/Getty Images

France and the United States appeared to question the purpose of such a mission, warning that any incriminating evidence had likely been removed by now.

"It is highly likely that evidence and essential elements disappear from the site, which is completely controlled by the Russian and Syrian armies," the French foreign ministry said.

The US ambassador to the OPCW, Ken Ward, had claimed Monday that the site and "may have tampered with it".

Russian foreign ministry spokeswoman Maria Zakharova hit back at France, calling the accusation "very surprising" and saying that Russia had supported the inspection.

Several experts have also said however that any investigation at this stage was likely to be inconclusive.

"As with any crime scene, it is crucial to get there as soon as possible," said Olivier Lepick, a fellow at the Paris-based Foundation for Scientific Research.

Inspectors have been in Damascus since SaturdayCredit:
REUTERS/Omar Sanadiki

"If the Russians and Syrians have nothing to hide, it's strange that they would wait 36 to 72 hours," he said. "It's probably to give themselves the time to finish cleaning up.”

In an impassioned defence to the European Parliament on Tuesday, France's President Emmanuel Macron admitted that Saturday's strikes had been a more political than military decision.

"Three countries have intervened, and let me be quite frank, quite honest - this is for the honour of the international community," he said in the French city of Strasbourg.